- Move verify_certificate functionality in schannel.c into a new
file called schannel_verify.c. Additionally, some structure defintions
from schannel.c have been moved to schannel.h to allow them to be
used in schannel_verify.c.
- Make verify_certificate functionality for Schannel available on
all versions of Windows instead of just Windows CE. verify_certificate
will be invoked on Windows CE or when the user specifies
CURLOPT_CAINFO and CURLOPT_SSL_VERIFYPEER.
- In verify_certificate, create a custom certificate chain engine that
exclusively trusts the certificate store backed by the CURLOPT_CAINFO
file.
- doc updates of --cacert/CAINFO support for schannel
- Use CERT_NAME_SEARCH_ALL_NAMES_FLAG when invoking CertGetNameString
when available. This implements a TODO in schannel.c to improve
handling of multiple SANs in a certificate. In particular, all SANs
will now be searched instead of just the first name.
- Update tool_operate.c to not search for the curl-ca-bundle.crt file
when using Schannel to maintain backward compatibility. Previously,
any curl-ca-bundle.crt file found in that search would have been
ignored by Schannel. But, with CAINFO support, the file found by
that search would have been used as the certificate store and
could cause issues for any users that have curl-ca-bundle.crt in
the search path.
- Update url.c to not set the build time CURL_CA_BUNDLE if the selected
SSL backend is Schannel. We allow setting CA location for schannel
only when explicitly specified by the user via CURLOPT_CAINFO /
--cacert.
- Add new test cases 3000 and 3001. These test cases check that the first
and last SAN, respectively, matches the connection hostname. New test
certificates have been added for these cases. For 3000, the certificate
prefix is Server-localhost-firstSAN and for 3001, the certificate
prefix is Server-localhost-secondSAN.
- Remove TODO 15.2 (Add support for custom server certificate
validation), this commit addresses it.
Closes https://github.com/curl/curl/pull/1325
- Fix warning 'integer from pointer without a cast' on 3rd arg in
CertOpenStore. The arg type HCRYPTPROV may be a pointer or integer
type of the same size.
Follow-up to e35b025.
Caught by Marc's CI builds.
Users can now specify a client certificate in system certificates store
explicitly using expression like `--cert "CurrentUser\MY\<thumbprint>"`
Closes#2376
When a zeroed out allocation is required, use calloc() rather than
malloc() followed by an explicit memset(). The result will be the
same, but using calloc() everywhere increases consistency in the
codebase and avoids the risk of subtle bugs when code is injected
between malloc and memset by accident.
Closes https://github.com/curl/curl/pull/2497
unit1309 and vtls/gtls: error: arithmetic on a null pointer treated as a
cast from integer to pointer is a GNU extension
Reported-by: Rikard Falkeborn
Fixes#2466Closes#2468
This reverts commit dc85437736.
libcurl (with the OpenSSL backend) performs server certificate verification
even if verifypeer == 0 and the verification result is available using
CURLINFO_SSL_VERIFYRESULT. The commit that is being reverted caused the
CURLINFO_SSL_VERIFYRESULT to not have useful information for the
verifypeer == 0 use case (it would always have
X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY).
Closes#2451
When targeting x64, MinGW-w64 complains about conversions between
32-bit long and 64-bit pointers. Fix this by reusing the
GNUTLS_POINTER_TO_SOCKET_CAST / GNUTLS_SOCKET_TO_POINTER_CAST logic
from gtls.c, moving it to warnless.h as CURLX_POINTER_TO_INTEGER_CAST /
CURLX_INTEGER_TO_POINTER_CAST.
Closes https://github.com/curl/curl/pull/2341
When peer verification is disabled, calling
SSL_CTX_load_verify_locations is not necessary. Only call it when
verification is enabled to save resources and increase performance.
Closes#2290
Follow-up to 84fcaa2e7. libressl does not have the API even if it says it is
late OpenSSL version...
Fixes#2246Closes#2247
Reported-by: jungle-boogie on github
Fixed undefined symbol of getenv() which does not exist when compiling
for Windows 10 App (CURL_WINDOWS_APP). Replaced getenv() with
curl_getenv() which is aware of getenv() absence when CURL_WINDOWS_APP
is defined.
Closes#2171
Prior to this change SSLKEYLOGFILE used line buffering on WIN32 just
like it does for other platforms. However, the Windows CRT does not
actually support line buffering (_IOLBF) and will use full buffering
(_IOFBF) instead. We can't use full buffering because multiple processes
may be writing to the file and that could lead to corruption, and since
full buffering is the only buffering available this commit disables
buffering for Windows SSLKEYLOGFILE entirely (_IONBF).
Ref: https://github.com/curl/curl/pull/1346#issuecomment-350530901
- Allow proxy_ssl to be checked for pending data even when connssl does
not yet have an SSL handle.
This change is for posterity. Currently there doesn't seem to be a code
path that will cause a pending data check when proxyssl could have
pending data and the connssl handle doesn't yet exist [1].
[1]: Recall that an https proxy connection starts out in connssl but if
the destination is also https then the proxy SSL backend data is moved
from connssl to proxyssl, which means connssl handle is temporarily
empty until an SSL handle for the destination can be created.
Ref: https://github.com/curl/curl/commit/f4a6238#commitcomment-24396542
Closes https://github.com/curl/curl/pull/1916
commit d3ab7c5a21 broke the boringssl build since it doesn't have
RSA_flags(), so we disable that code block for boringssl builds.
Reported-by: W. Mark Kubacki
Fixes#2117
... since the 'tv' stood for timeval and this function does not return a
timeval struct anymore.
Also, cleaned up the Curl_timediff*() functions to avoid typecasts and
clean up the descriptive comments.
Closes#2011
... to cater for systems with unsigned time_t variables.
- Renamed the functions to curlx_timediff and Curl_timediff_us.
- Added overflow protection for both of them in either direction for
both 32 bit and 64 bit time_ts
- Reprefixed the curlx_time functions to use Curl_*
Reported-by: Peter Piekarski
Fixes#2004Closes#2005
Those were temporary things we'd add and remove for our own convenience
long ago. The last few stayed around for too long as an oversight but
have since been removed. These days we have a running
BORINGSSL_API_VERSION counter which is bumped when we find it
convenient, but 2015-11-19 was quite some time ago, so just check
OPENSSL_IS_BORINGSSL.
Closes#1979
Compare these settings in Curl_ssl_config_matches():
- verifystatus (CURLOPT_SSL_VERIFYSTATUS)
- random_file (CURLOPT_RANDOM_FILE)
- egdsocket (CURLOPT_EGDSOCKET)
Also copy the setting "verifystatus" in Curl_clone_primary_ssl_config(),
and copy the setting "sessionid" unconditionally.
This means that reusing connections that are secured with a client
certificate is now possible, and the statement "TLS session resumption
is disabled when a client certificate is used" in the old advisory at
https://curl.haxx.se/docs/adv_20170419.html is obsolete.
Reviewed-by: Daniel Stenberg
Closes#1917
.. and include the core NTLM header in all NTLM-related source files.
Follow up to 6f86022. Since then http_ntlm checks NTLM_NEEDS_NSS_INIT
but did not include vtls.h where it was defined.
Closes https://github.com/curl/curl/pull/1911
With the recently introduced MultiSSL support multiple SSL backends
can be compiled into cURL That means that now the order of the SSL
One option would be to use the same SSL backend as was configured
via `curl_global_sslset()`, however, NTLMv2 support would appear
to be available only with some SSL backends. For example, when
eb88d778e (ntlm: Use Windows Crypt API, 2014-12-02) introduced
support for NTLMv1 using Windows' Crypt API, it specifically did
*not* introduce NTLMv2 support using Crypt API at the same time.
So let's select one specific SSL backend for NTLM support when
compiled with multiple SSL backends, using a priority order such
that we support NTLMv2 even if only one compiled-in SSL backend can
be used for that.
Ref: https://github.com/curl/curl/pull/1848
In some cases the RSA key does not support verifying it because it's
located on a smart card, an engine wants to hide it, ...
Check the flags on the key before trying to verify it.
OpenSSL does the same thing internally; see ssl/ssl_rsa.c
Closes#1904
lib/vtls/openssl.c uses OpenSSL APIs from BUF_MEM and BIO APIs. Include
their headers directly rather than relying on other OpenSSL headers
including things.
Closes https://github.com/curl/curl/pull/1891
Another mistake in my manual fixups of the largely mechanical
search-and-replace ("connssl->" -> "BACKEND->"), just like the previous
commit concerning HTTPS proxies (and hence not caught during my
earlier testing).
Fixes#1855Closes#1871
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
In d65e6cc4f (vtls: prepare the SSL backends for encapsulated private
data, 2017-06-21), this developer prepared for a separation of the
private data of the SSL backends from the general connection data.
This conversion was partially automated (search-and-replace) and
partially manual (e.g. proxy_ssl's backend data).
Sadly, there was a crucial error in the manual part, where the wrong
handle was used: rather than connecting ssl[sockindex]' BIO to the
proxy_ssl[sockindex]', we reconnected proxy_ssl[sockindex]. The reason
was an incorrect location to paste "BACKEND->"... d'oh.
Reported by Jay Satiro in https://github.com/curl/curl/issues/1855.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Ever since 70f1db321 (vtls: encapsulate SSL backend-specific data,
2017-07-28), the code handling HTTPS proxies was broken because the
pointer to the SSL backend data was not swapped between
conn->ssl[sockindex] and conn->proxy_ssl[sockindex] as intended, but
instead set to NULL (causing segmentation faults).
[jes: provided the commit message, tested and verified the patch]
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
... instead of the prefix-less version since WolfSSL 3.12 now uses an
enum with that name that causes build failures for us.
Fixes#1865Closes#1867
Reported-by: Gisle Vanem
This is an adaptation of 2 of Peter Wu's SSLKEYLOGFILE implementations.
The first one, written for old OpenSSL versions:
https://git.lekensteyn.nl/peter/wireshark-notes/tree/src/sslkeylog.c
The second one, written for BoringSSL and new OpenSSL versions:
https://github.com/curl/curl/pull/1346
Note the first one is GPL licensed but the author gave permission to
waive that license for libcurl.
As of right now this feature is disabled by default, and does not have
a configure option to enable it. To enable this feature define
ENABLE_SSLKEYLOGFILE when building libcurl and set environment
variable SSLKEYLOGFILE to a pathname that will receive the keys.
And in Wireshark change your preferences to point to that key file:
Edit > Preferences > Protocols > SSL > Master-Secret
Co-authored-by: Peter Wu
Ref: https://github.com/curl/curl/pull/1030
Ref: https://github.com/curl/curl/pull/1346
Closes https://github.com/curl/curl/pull/1866
Up2date versions of OpenSSL maintain the default reasonably secure
without breaking compatibility, so it is better not to override the
default by curl. Suggested at https://bugzilla.redhat.com/1483972Closes#1846
Previously, we used as default SSL backend whatever was first in the
`available_backends` array.
However, some users may want to override that default without patching
the source code.
Now they can: with the --with-default-ssl-backend=<backend> option of
the ./configure script.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When only one SSL backend is configured, it is totally unnecessary to
let multissl_init() configure the backend at runtime, we can select the
correct backend at build time already.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Let's add a compile time safe API to select an SSL backend. This
function needs to be called *before* curl_global_init(), and can be
called only once.
Side note: we do not explicitly test that it is called before
curl_global_init(), but we do verify that it is not called multiple times
(even implicitly).
If SSL is used before the function was called, it will use whatever the
CURL_SSL_BACKEND environment variable says (or default to the first
available SSL backend), and if a subsequent call to
curl_global_sslset() disagrees with the previous choice, it will fail
with CURLSSLSET_TOO_LATE.
The function also accepts an "avail" parameter to point to a (read-only)
NULL-terminated list of available backends. This comes in real handy if
an application wants to let the user choose between whatever SSL backends
the currently available libcurl has to offer: simply call
curl_global_sslset(-1, NULL, &avail);
which will return CURLSSLSET_UNKNOWN_BACKEND and populate the avail
variable to point to the relevant information to present to the user.
Just like with the HTTP/2 push functions, we have to add the function
declaration of curl_global_sslset() function to the header file
*multi.h* because VMS and OS/400 require a stable order of functions
declared in include/curl/*.h (where the header files are sorted
alphabetically). This looks a bit funny, but it cannot be helped.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
There is information about the compiled-in SSL backends that is really
no concern of any code other than the SSL backend itself, such as which
function (if any) implements SHA-256 summing.
And there is information that is really interesting to the user, such as
the name, or the curl_sslbackend value.
Let's factor out the latter into a publicly visible struct. This
information will be used in the upcoming API to set the SSL backend
globally.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When building software for the masses, it is sometimes not possible to
decide for all users which SSL backend is appropriate.
Git for Windows, for example, uses cURL to perform clones, fetches and
pushes via HTTPS, and some users strongly prefer OpenSSL, while other
users really need to use Secure Channel because it offers
enterprise-ready tools to manage credentials via Windows' Credential
Store.
The current Git for Windows versions use the ugly work-around of
building libcurl once with OpenSSL support and once with Secure Channel
support, and switching out the binaries in the installer depending on
the user's choice.
Needless to say, this is a super ugly workaround that actually only
works in some cases: Git for Windows also comes in a portable form, and
in a form intended for third-party applications requiring Git
functionality, in which cases this "swap out libcurl-4.dll" simply is
not an option.
Therefore, the Git for Windows project has a vested interest in teaching
cURL to make the SSL backend a *runtime* option.
This patch makes that possible.
By running ./configure with multiple --with-<backend> options, cURL will
be built with multiple backends.
For the moment, the backend can be configured using the environment
variable CURL_SSL_BACKEND (valid values are e.g. "openssl" and
"schannel").
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
So far, all of the SSL backends' private data has been declared as
part of the ssl_connect_data struct, in one big #if .. #elif .. #endif
block.
This can only work as long as the SSL backend is a compile-time option,
something we want to change in the next commits.
Therefore, let's encapsulate the exact data needed by each SSL backend
into a private struct, and let's avoid bleeding any SSL backend-specific
information into urldata.h. This is also necessary to allow multiple SSL
backends to be compiled in at the same time, as e.g. OpenSSL's and
CyaSSL's headers cannot be included in the same .c file.
To avoid too many malloc() calls, we simply append the private structs
to the connectdata struct in allocate_conn().
This requires us to take extra care of alignment issues: struct fields
often need to be aligned on certain boundaries e.g. 32-bit values need to
be stored at addresses that divide evenly by 4 (= 32 bit / 8
bit-per-byte).
We do that by assuming that no SSL backend's private data contains any
fields that need to be aligned on boundaries larger than `long long`
(typically 64-bit) would need. Under this assumption, we simply add a
dummy field of type `long long` to the `struct connectdata` struct. This
field will never be accessed but acts as a placeholder for the four
instances of ssl_backend_data instead. the size of each ssl_backend_data
struct is stored in the SSL backend-specific metadata, to allow
allocate_conn() to know how much extra space to allocate, and how to
initialize the ssl[sockindex]->backend and proxy_ssl[sockindex]->backend
pointers.
This would appear to be a little complicated at first, but is really
necessary to encapsulate the private data of each SSL backend correctly.
And we need to encapsulate thusly if we ever want to allow selecting
CyaSSL and OpenSSL at runtime, as their headers cannot be included within
the same .c file (there are just too many conflicting definitions and
declarations for that).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
At the moment, cURL's SSL backend needs to be configured at build time.
As such, it is totally okay for them to hard-code their backend-specific
data in the ssl_connect_data struct.
In preparation for making the SSL backend a runtime option, let's make
the access of said private data a bit more abstract so that it can be
adjusted later in an easy manner.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
In the ongoing endeavor to abstract out all SSL backend-specific
functionality, this is the next step: Instead of hard-coding how the
different SSL backends access their internal data in getinfo.c, let's
implement backend-specific functions to do that task.
This will also allow for switching SSL backends as a runtime option.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
There are convenient no-op versions of the init/cleanup functions now,
no need to define private ones for axTLS.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
These functions are all available via the Curl_ssl struct now, no need
to declare them separately anymore.
As the global declarations are removed, the corresponding function
definitions are marked as file-local. The only two exceptions here are
Curl_mbedtls_shutdown() and Curl_polarssl_shutdown(): only the
declarations were removed, there are no function definitions to mark
file-local.
Please note that Curl_nss_force_init() is *still* declared globally, as
the only SSL backend-specific function, because it was introduced
specifically for the use case where cURL was compiled with
`--without-ssl --with-nss`. For details, see f3b77e561 (http_ntlm: add
support for NSS, 2010-06-27).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The _shutdown() function calls the _session_free() function; While this
is not a problem now (because schannel.h declares both functions), a
patch looming in the immediate future with make all of these functions
file-local.
So let's just move the _session_free() function's definition before it
is called.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The connect_finish() function (like many other functions after it) calls
the Curl_axtls_close() function; While this is not a problem now
(because axtls.h declares the latter function), a patch looming in the
immediate future with make all of these functions file-local.
So let's just move the Curl_axtls_close() function's definition before
it is called.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The entire idea of introducing the Curl_ssl struct to describe SSL
backends is to prepare for choosing the SSL backend at runtime.
To that end, convert all the #ifdef have_curlssl_* style conditionals
to use bit flags instead.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The SHA-256 checksumming is also an SSL backend-specific function.
Let's include it in the struct declaring the functionality of SSL
backends.
In contrast to MD5, there is no fall-back code. To indicate this, the
respective entries are NULL for those backends that offer no support for
SHA-256 checksumming.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The MD5 summing is also an SSL backend-specific function. So let's
include it, offering the previous fall-back code as a separate function
now: Curl_none_md5sum(). To allow for that, the signature had to be
changed so that an error could be returned from the implementation
(Curl_none_md5sum() can run out of memory).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This is the first step to unify the SSL backend handling. Now all the
SSL backend-specific functionality is accessed via a global instance of
the Curl_ssl struct.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The idea of introducing the Curl_ssl struct was to unify how the SSL
backends are declared and called. To this end, we now provide an
instance of the Curl_ssl struct for each and every SSL backend.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This new struct is similar in nature to Curl_handler: it will define the
functions and capabilities of all the SSL backends (where Curl_handler
defines the functions and capabilities of protocol handlers).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This patch makes the signature of the _sha256sum() functions consistent
among the SSL backends, in preparation for unifying the way all SSL
backends are accessed.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This patch makes the signature of the _data_pending() functions
consistent among the SSL backends, in preparation for unifying the way
all SSL backends are accessed.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This patch makes the signature of the _cleanup() functions consistent
among the SSL backends, in preparation for unifying the way all SSL
backends are accessed.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
... as the previous fixed length 128 bytes buffer was sometimes too
small.
Fixes#1823Closes#1831
Reported-by: Benjamin Sergeant
Assisted-by: Bill Pyne, Ray Satiro, Nick Zitzmann
clang complains:
vtls/darwinssl.c:40:8: error: extra tokens at end of #endif directive
[-Werror,-Wextra-tokens]
This breaks the darwinssl build on Travis. Fix it by making this token
a comment.
Closes https://github.com/curl/curl/pull/1734
... to make all libcurl internals able to use the same data types for
the struct members. The timeval struct differs subtly on several
platforms so it makes it cumbersome to use everywhere.
Ref: #1652Closes#1693
... causing a SIGSEGV in showit() in case the handle used to initiate
the connection has already been freed.
This commit fixes a bug introduced in curl-7_19_5-204-g5f0cae803.
Reported-by: Rob Sanders
Bug: https://bugzilla.redhat.com/1436158
- Change gnutls pointer/int macros to pointer/curl_socket_t.
Prior to this change they used long type as well.
The size of the `long` data type can be shorter than that of pointer
types. This is the case most notably on Windows.
If C99 were acceptable, we could simply use `intptr_t` here. But we
want to retain C89 compatibility.
Simply use the trick of performing pointer arithmetic with the NULL
pointer: to convert an integer `i` to a pointer, simply take the
address of the `i`th element of a hypothetical character array
starting at address NULL. To convert back, simply cast the pointer
difference.
Thanks to Jay Satiro for the initial modification to use curl_socket_t
instead of int/long.
Closes#1617
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
cyassl/ssl.h needs the macros from cyassl/options.h, so define them
before including cyassl/ssl.h the first time, which happens in
urldata.h.
This broke the build on Ubuntu Xenial, which comes with WolfSSL 3.4.8
and therefore redefines the symbols from cyassl/options.h instead of
including the header.
Closes https://github.com/curl/curl/pull/1536
The module contains a more comprehensive set of trust information than
supported by nss-pem, because libnssckbi.so also includes information
about distrusted certificates.
Reviewed-by: Kai Engert
Closes#1414
- Track when the cached encrypted data contains only a partial record
that can't be decrypted without more data (SEC_E_INCOMPLETE_MESSAGE).
- Change Curl_schannel_data_pending to return false in such a case.
Other SSL libraries have pending data functions that behave similarly.
Ref: https://github.com/curl/curl/pull/1387
Closes https://github.com/curl/curl/pull/1392
This fixes 3 warnings issued by MinGW:
1. PR_ImportTCPSocket actually has a paramter of type PROsfd instead of
PRInt32, which is 64 bits on Windows. Fixed this by including the
corresponding header file instead of redeclaring the function, which is
supported even though it is in the private include folder. [1]
2. In 64-bit mode, size_t is 64 bits while CK_ULONG is 32 bits, so an explicit
narrowing cast is needed.
3. Curl_timeleft returns time_t instead of long since commit
21aa32d30d.
[1] https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_ImportTCPSocket
Closes https://github.com/curl/curl/pull/1393
ERR_error_string with NULL parameter is not thread-safe. The library
writes the string into some static buffer. Two threads doing this at
once may clobber each other and run into problems. Switch to
ERR_error_string_n which avoids this problem and is explicitly
bounds-checked.
Also clean up some remnants of OpenSSL 0.9.5 around here. A number of
comments (fixed buffer size, explaining that ERR_error_string_n was
added in a particular version) date to when ossl_strerror tried to
support pre-ERR_error_string_n OpenSSLs.
Closes#1424
ssl_session_init was only introduced in version 1.3.8, the penultimate
version. The function only contains a memset, so replace it with that.
Suggested-by: Jay Satiro
Fixes https://github.com/curl/curl/issues/1401
... because they may include an intermediate certificate for a client
certificate and the intermediate certificate needs to be presented to
the server, no matter if we verify the peer or not.
Reported-by: thraidh
Closes#851
When UNICODE is not defined, the Curl_convert_UTF8_to_tchar macro maps
directly to its argument. As it is declared as a pointer to const and
InitializeSecurityContext expects a pointer to non-const, both MSVC and MinGW
issue a warning about implicitly casting away the const. Fix this by declaring
the variables as pointers to non-const.
Closes https://github.com/curl/curl/pull/1394
- If SSL_get_error is called but no extended error detail is available
then show that SSL_ERROR_* as a string.
Prior to this change there was some inconsistency in that case: the
SSL_ERROR_* code may or may not have been shown, or may have been shown
as unknown even if it was known.
Ref: https://github.com/curl/curl/issues/1300
Closes https://github.com/curl/curl/pull/1348
